Fluke CableAnalyzer DSX-5000, Техническое справочное руководство, Страница: 356 / 700

Versiv Series Cabling Certification Product Family
Technical Reference Handbook
320
About Launch and Tail Cords
Launch and tail cords let the tester measure the loss and
reflectance of the first and last connectors in the cabling and also
include them in the measurement of overall loss. Without launch
and tail cords, no backscatter is available before the first
connector nor after the last. To measure the properties of a
connector, the tester must measure the backscatter before and
after the connector.
The launch cord also lets the you see events that are close to the
OTDR. Without a launch fiber, those events can be hidden by the
large reflection caused by the OTDR’s port.
Fluke Networks recommends that you use launch and tail cords.
You should also use the launch/tail cord compensation function
to remove the lengths and attenuation of these fibers from the
OTDR measurements.
If you select a test limit that requires you to use launch and tail
cords, the tester shows a warning message when you try to do an
OTDR test without launch and tail cords.
W
Caution

For tests on cabling that has angled physical contact
(APC) connectors, use only launch/tail cords that
have APC connectors at the ends connected to the
cabling. Other connector types cause large
reflections that can cause unreliable test results.

Make sure the end of the launch cord you connect
to the OTDR port has the correct type of connector,
UPC or APC, for the OTDR module. OptiFiber Pro
modules have UPC ports. OptiFiber Pro HDR
modules have APC ports. Connecting the wrong
type of connector can damage the OTDR port, and
the large reflection at the OTDR port can cause
unreliable test results.